Thermoluminiscence in alkali halides irradiated at 80K

The thermoluminiscence, the thermally stimulated currents and the thermal stability of the F centers induced in pure NaCl and KCl crystals by X irradiation at 80K have been studied in detail, in the range between 80 and 300K. The thermoluminiscent processes induced by illumination at 80K with F light in samples previously irradiated at room temperature has also been studied. It has been clearly observed the existence of thermoluminiscent processes due to electrons and holes thermally released from traps, in which the F centers are not involved. The existence of hole-F center recombination has not been observed. There are several thermoluminiscent processes in both materials which are scribed to the recombination of F centers with mobile interstitial halogen atoms thermally released from traps, which are likely monovalent impurities in this temperature interval. The light emitting stage in these processes is originated by the formation of self trapped excitons. (author)